The present invention relates to a device for articulating a tire-pressure sensor on the rim of a motor vehicle. More specifically, this articulation is between a valve base and an electronic unit processing the signals delivered by the tire-pressure sensor.
It is already known practice for a motor vehicle to be fitted with tire-pressure sensors. In general, each wheel of the vehicle has a pressure sensor placed on its rim inside the tire. These sensors are designed in particular to measure the pressure inside the tire and are, for this purpose, placed in an electronic unit also comprising means for processing the measured signal and for emitting this signal to a receiver placed inside the vehicle. If the pressure in one of the tires varies abnormally, a warning (an audible message, a visual message, etc.) alerts the driver to the detected anomaly. The driver is also informed of the position of the defective wheel. As these methods of processing the signal and of determining anomalies are known per se, they will not be detailed hereinafter.
It is already known practice for the tire-pressure sensor electronic unit to be fixed at the valve used for inflating the tires. Advantageously, by tightening a nut that secures this valve to the rim, the entire electronic unit can be fixed to the rim.
For this, the unit is designed to accommodate the valve base and to tilt toward the rim (so as to be pressed against the bottom of the rim) while the valve is being screwed onto the rim. Such an example of securing is described, for example, in patent applications FR 0110843 and FR 0111539 in the name of the Applicant Company.
The valve base is therefore articulated with respect to the electronic unit either through a set of two off-axis stops, or by the folding of a bellows. These solutions are satisfactory and allow the unit to be pressed against the bottom of the rim whatever the size of this rim (different radii of curvature). However, these solutions are relatively expensive to implement and involve a valve base equipped with extensions that are relatively difficult to produce.
The purpose of the present invention is to create an articulation between a valve base and a unit able to press the unit against the bottom of the rim regardless of the diameter of this rim. This articulation needs to remain simple to manufacture and inexpensive.
To this end, the present invention relates to a device for articulating a tire-pressure sensor to a motor vehicle rim, said device consisting of:
a tire-inflation valve having a base designed to come into contact with a corresponding part of a tire-pressure sensor electronic unit, said valve further having a threaded shank designed to be introduced through an orifice in a wheel rim and to protrude outward from this rim, said valve base being situated in the continuation of the shank inside the rim, and
a tire-pressure electronic unit housing the valve base, said unit being pressed against the bottom of the rim by tightening a securing nut onto the threaded part of the shank of the valve,
said articulating device being characterized in that the valve base has a roughly spherical part collaborating with a region of corresponding shape formed on the electronic unit.
Advantageously, the valve base and the part of the unit in contact with this valve base are equipped with a plurality of facets. The collaboration between a facet belonging to the valve base and one of the facets belonging to the unit allows the angle of inclination between the valve and the unit to be set. As a result, the unit nestles perfectly (according to the radius of curvature of the rim) in the bottom of the rim.
Depending on the number of facets made on the valve base and on the unit, there are a certain number of possible angles of inclination between the valve and the unit. All that is required is to choose a suitable pair of facets (one on the valve base and one on the unit) in order to press the unit against the rim according to the radius of curvature of this rim.
As an alternative, the spherical part of the valve base is in direct contact with a spherical part of the unit. These two parts have no facets. They do, however, have means of slip-free clamping of one with respect to the other (studs and grooves for example). In this case, as the valve securing nut is tightened onto the shank, all that is required is for the unit to be pushed against the rim in order to adjust the angle of inclination of the unit with respect to the rim. The tilting of the unit in the bottom of the rim during tightening is therefore done by hand.
Advantageously, a reinforcing piece is placed between the unit and the rim so as to avoid any problem of these two elements hammering together.